BOOK REVIEWS 193

(due to salt mobility) of collecting accurately dated material. Both factors may exert a significant effect on the sulphur isotope age curve. A still further source of difficulty lies in the additions of sulphur from subaerial and submarine volcanisms, which Lein and lvanov argue have made significant, and variable contributions to the exogenic cycle in the geological past. Perhaps the way forward is to construct more complex models, which inte- grate both mass and isotopic data to produce solutions which most closely satisfy both constraints.

The second part of this text comprises just one chapter, by Brimblecombe et a/. which considers anthropogenic influences on the sulphur cycle and especially on the atmosphere. First the global atmospheric sulphur budget is up-dated from the earlier SCOPE 19 publications and this cycle is then compared to the prehistorical cycle, suggesting that global sulphur emission into the atmos- phere have increased twentyfold over the last 120 years. By contrast the increases in the riverine and aeolian flux (approximately doubled) are small but not as well known. These sulphur budget data are an authoritative summary of the huge scientific effort which has been expended since SCOPE 19 was published in 1983, yet there are still alarming gaps in our knowledge. The chapter concludes with a review of the data from records of past fluxes and some suggestions as to future work. It is very much in agreement with the reviewers prejudice in identifying sulphur isotope studies as being potentially valuable but very underdeveloped. Given the scarcity of U.K. sulphur isotope facilities, and the relatively large amounts of manpower needed for sample preparation, an atmospheric sulphur isotope facility is clearly needed.

The third, and last section, contains three chapters under the heading ‘Interaction of Sulphur and Carbon Cycles in Some Ecosystems’. In the first chapter Ivanov et al. produce an extremely comprehensive review of S-C interactions in marine sediments. This assembles a wealth of useful data on rates of primary production and sulphate reduction, together with estimates of organic matter consumption by aerobic and anaerobic processes. Compilations of these data are otherwise scattered widely through the literature and their collection here is a valu- able achievement for geologists interested in organic

matter consumption and preservation. Better still are the final 20 pages which detail our current state of knowledge with respect to anaerobic methane oxidation and meth- anogenesis. My belief is that these processes represent the next ‘hot’ area for modern sediment studies - they are still readily accessible by existing coring and collec- tion techniques, and the extent to which their products diffuse or advect upwards into the sulphate reduction zone are not well known. The answers to these questions are absolutely critical for the identification of methano- genic signatures in ancient carbonates (Table 6.8 indi- cates the scale of this problem, documenting 6°C for coexisting CO, and CH,).

The next chapter reviews ‘Sulphur Emission and Transformation at Deep Sea Hydrothermal Vents’, but lacks detail and is all too brief. I would have liked to see more numerical data included and critically evalu- ated, especially that relevant to the different sulphur fluxes and their isotope composition.

However the third chapter in this section is another tour de force, dealing with the ‘Interaction of Sulphur and Carbon Cycles in Microbial Mats’. The significance of microbial mats derives in part from their links between primary production of autochthonous organic matter and its mineralization without the intervention of other decomposition processes. Cyanobacterial mats are also the oldest known biogenic sedimentary structure. The chapter is written mainly from a microbiological view- point, but the first part deals with mats in hypersaline environments and would repay study by geochemists interested in these environments. The latter part of the chapter deals with hot springs, which are not of quantita- tive significance in a global context. There is here, however, considerable biochemical and microbiological detail against which useful comparisons may be made with hydrothermal bent communities.

Overall, the text represents a valuable addition to the sulphur geochemistry library. It has been slow in prep- aration (few references post-date 1984) but is almost flawless in production. It will remain a significant source of data for many years to come.

R. RAISWELL

lNTRODUCTION T O THE PHYSICS OF THE EARTH’S INTERIOR by J. P. Poirier, Cambridge Topics in Mineral Physics and Chemistry 3, Cambridge University Press. Price: E40.00 hardback, E l 7.50 paper- back.

Though the title does not suggest it, this book is in two rather distinct parts. The first part, forming the bulk of the book, is a discussion of material properties such as elasticity, heat capacity, thermal conductivity and so on; how they are linked (via thermodynamics), and how they may be predicted under conditions outside the range accessible in experiments. This is quite a general discus-

sion, without a particular focus on materials within the Earth, although the predictive techniques described are obviously those in use by Earth modellers. Only in the last chapter ~ ‘Earth models’ ~ is the actual planet analysed in any detail. There is a gap between the two parts of the book which the author does not quite bridge successfully - nevertheless, it is full of interesting and, for me, new information.

The first part begins with a summary of basic thermo- dynamics, then a discussion of elasticity from the con- tinuum viewpoint, including fundamentals such as the relation between seismic velocities and elastic moduli. This is followed by a more advanced treatment of lattice

I94 BOOK REVIEWS

vibrations which allows prediction of elastic and thermal hehaviour of crystalline materials. The next chapter, on equations of state, discusses both theoretical predictions of, and experimental techniques for determining, the EOS for a material under extremely high pressures. Melt- ing point, in principal predictable from the equations of state for solid and liquid. must in fact be inferred by a variety of techniques o f varying reliability discussed in chapter 5. The first five chapters are thus on aspects of material properties at equilibrium. Transport proper- ties, such as viscosity, thermal and electric conductivity, are summarized in Chapter 6.

T M . ~ things characterize these discussions: brevity, and uncompromising mathematics. Much ofthe early mater- ial is so condensed that it could only he useful to a reader already familiar with the subjects under discussion, though it then forms a useful summary. For instance, viscosity gets half a page on p. 136. A background in continuum mechanics and quantum mechanics is necess- ary to gain much from parts o f t h e study, such iis the chapter on lattice dynamics. and I would be surprised if the mathematical aspects or this material were access- ible to many Earth science undergraduates. More impor- tantly, it is often unclcar where the author is coming from and going to one awaits with interest the payoll in the final chapter, when all these material properties are illustrated with respect to derivation of the Earth model. This does not always come! For instance the detailed discussion of dithsioti mechanisms in Chapter 6 seems to have no relevance to the probleins highlighted in the final chapter.

I n this last chapter, seismological, thermal and mineralogical aspects of Earth models are summarized. Whilst some reference is made to the way in which these models are constrained by reference to the framework of techniques in previous chapters, it is not clear how this is done in detail. The reader is aware that some sort of ‘best fit’ of materials to the observed seismological data is generated in the model, but is told little more. This last, single, chapter could be substantially enlarged to tic together earlier themes.

In spite of these adverse comments, the book has much to commend it: first, it is interesting - the first parts to anyone involved in materials, however deep they may he in the Earth; the last chapter, with its analysis of two-layer versus whole mantle convection thcorics and other problems, t o any Earth scientist concerned with large-scale processes. Secondly, it provides an excellent ‘way in’ to different aspects of the subject, by presenting an array of different viewpoints on contentious issues and backing this with a substantial reference list. Poirier manages to voice his own opinion without swamping the issue: thus, for example, it is clear he is sceptical of the applicability of the ‘shear instability’ model for melting - a model which claims that a solid will melt when its shear modulus decreases to 7ero ~~ but still gives it a decent airing. Thirdly, 1 know of no other book summarizing the information in this work. Thus, the book is good value and I am sure that i t will he used both by those on a long sabbatical to the deep inantle and core and by those on a day trip.

J o t i N WHEELER

APPLIED CHEMICAL. A N D ISOTOPIC CiKOLJND- WATER HYDROLOGY by E. Mazor, Wiley, Chiches- ter, 1991. No. of pages: 274. Price f39.00 (hardback).

This book deals with the physical, chemical and isoto- pic properties of groundwater and how they might be used t o understand water systems. I t is designed to he a n introductory text aimed a t people ofa variety ofdisci- plines who need to collect water samples for various pur- poses, probably many of them with little or n o prior knowledge ofchemistry or geology. The first fivechapters contain a basic introduction to geological and hydrogeo- logical concepts and also to the physical and chcmical parameters needed in field studies. Further chaplers deal with data processing and planning hydrochemical studies with four chapters dealing with isotopic and noble gas tech ti iques.

The reader is left with much to do for herihirnself. In particular, no guidance is given on sampling tech- niques nor on analytical methods that are appropriate for water analysis. The author recommends that this is discussed with the laboratories or with experts, whereas some authoritative help in these two important areas, especially sampling, ought to be given in such a text. This underlines the main weakness of the book. Unless

the reader/sampler understands what the analysis is for and collects or commissions samples according to the correct procedures, the data collected will be worthless.

There is a strong contrast in the hook between the quite detailed and generally sound treatment ofthe isoto- pic applications in hydrochemical studies with the more casunl and often inadequate treatment of the major ion geochemical data. This is a pity since the person to whom the hook is directed needs a solid grounding in how to interpret data from inexpensive hasic techniques before being introduced to radioisotopes and inert gases, for example, which they are likely to use infrcqucntly if at all.

The section on data interpretation is weak and does riot mention many of the more widely used methods of representation (trilinear diagrams for cxamplc). Much of the value of hydrochemical studies lies i i i an apprecia- tion of the water rock interactions involved. This is only briefly dealt with in this book. There is not even a men- tion of equilibrium concepts. I f the author had referred to the carbonate system, for example, he would have been able to introduce the reiider to the important areas of mineral equilibrium and solubility. Much of the important pioneering hydrogeochemical work of R . M. Carrels and his coworkers has been ignored in this book.